Gottlieb System 80b switch matrix question

[brad808]

Hey guys I picked up a Hollywood Heat tonight and am having a problem with closed switches. When I check the switch matrix I'm getting a whole column out (1,11,21,31,41,51,61,71) are all showing closed. Any help as to where to start looking is appreciated. I tried swapping the two circuit boards with the diode strips under the playfield but the problem continued. Would I be correct in assuming one of the matrix ICs is gone bad or possibly bad connection? If so which one should I be looking at?

Thanks for any help and be gentle I'm pin noob 

[brad808]

http://www.pinwiki.com/wiki/index.php?title=File:Gtb_sys80_cpu_divided.png

Looking at that diagram I'm thinking there could possibly be a problem with z13 or z14 the switch return ICs? Maybe tonight I can try and swap them around and see if the problem moves to another row?

[brad808]

You need to physically inspect every stuck switch on that column.  You also need to check every diode  associated with those switches.  Any funny business with a shorted diode, stuck switch, or switch touching ground can cause that problem.

Thanks Jim I think (hope) I have it narrowed down now. I checked all the switches and there were no contacts, I physically replaced the entire diode strip with another one. That left me with the chips. Someone had previously repaired them. I swapped two of them out of their sockets and the problem moved to a new set of switches. I'm thinking that probably means the solder on the sockets is ok but one of the chips will need to be replaced. Now I just need to source them.

Sent from my Desire HD

[ed12]

hi
go slow and follow the advice here
pray it is not a :riot: chip..

ed

[brad808]

Well time for me to admit my first mistake with it.... IC z12 and z13 are different chips! whoops, damn letters are so small z11,12 are 4704 series chips and z13,z14 are 4700 series chips. Guess its back to the drawing board.

Right now I have 10,11,20,21,30,31,40,41 etc all showing closed switches

Now if i unplug the j6 connector where all the switches return shouldn't all the switches show disconnected?

[ed12]

hi
 the link u posted is for a system 80 not a system 80b
the dif is the 80b used olny 2 eprom's 1 of which is on a piggy-back board
also the :riot: chip control's the matrix

ed

[ed12]

hi
now as ic11/12 are your strobe's ie send singal
and ic13/14 are your return's :from switch-diode-matrix:
and u found no known diode short's ?
also as u are board level repair >fussy-little-pesky-trace's<
do not remove the :riot: chip unless u know,how to remove them without
doing damage to the main board,in the trade we call them burchtered
and will not touch them
u must do a few more chk's.look at the riot for a soild gnd..ie pulled low
or a constant high ie pulled high..this will apply to the i/o line's olny
this will tell u if u have a bad riot or a bad ic or a bad switch and or a bad diode in the matrix
go slow think it out
look at the board and copy a pic in i can tell u if is a 80/80a/80b/80c
c the point please
post back

ed

[brad808]

OK I have a bit of an update on this. I replaced z11,z12,z13,z14,z15. The game booted up and I went to test mode all switches showed closed. I credited up and played 2 or 3 games. Everything seemed fine. My girlfriend played 2 or 3 games then she only got 2 balls one game, the next game she only got 1 ball. Now when I boot it up it simply shows weird graphics in the display. When I hit the left advance button the game tries to start as if I'm hitting the start button and then the left ball capture keeps triggering a kick out. Can you explain in more detail how I can check the riot chip? I'm guessing by the fact that she game worked after replacing those chips that they were a side effect of a greater problem. Obviously something is going wrong and fried those chips.

I've checked every diode I can possibly find with a multimeter, physically looked at all the switches and still haven't been able to find anything.

[ed12]

hi
the riot chip is a bugger to chk
unless u have a spare system80/a/b/c on hand ?
let me ask u 1 question before we go to debug mode
is there any evedince of battery damage ?,u can tell this by looking
at the trace's below where the oringal battery would be
and see if the trace's are a tad lighter :green: then the reset
if this has happened >common< then we can track it down to a bad/brocken trace,which is what it put's me in mind off
but we need to start there,40 pin's can be indanunting for alot of ppl
to un-solder-re-solder

ed

[brad808]

There is no battery damage that I can see. A previous owner has done the battery mod and the ground mods on this game. I've checked all those connections and they seem to be fine. Last night somebody sent me this via email last night. It's basically a bible of system80 repairs. Before this I'd simply been looking on the internet and reading the schematics. This is what it says.

The RIOT Chips.
Chip U4, U5 and U6 are 6532 RIOT chips. These are large 40 pin chips, and often
they fail. If any one of the RIOT chips fails, that can lock up the CPU board. RIOT
U4 handles the switch matrix, and this chip is particularly troublesome. If any of
RIOT U4's input TTL chips at Z11/Z12 (7404 switch strobes/row) and Z13/Z14 (7400
switch returns/columns) fail, this can lock the CPU board. Also the Z15 switch
returns enable chip (7432) can cause switch matrix problems too:
For example, if Z12 is missing or failed, the CPU board will not boot. Also if chip Z14
is missing or failed, the CPU board comes up immediately with "000000" in the
displays (like the slam switch is open). Note row chip Z11 and column chip Z13 can
be missing and the CPU board will still boot (because it doesn't handle the slam
switch).
Switch matrix chips Z13, Z14 (7400 returns/columns) input pins 1,2,4,5,9,10,12,13
can be viewed with a logic probe. They should be strobing, as they are the switch
returns, and connect directly to the playfield switches. None of these should be
stuck low! If one is stuck low, the CPU board may not boot (by forcing the IRQ low).
Then test the Z13, Z14 output pins 3,6,8,11. If these outputs are all strobing, but
an input is not, replace the chip (7400). If neither the input or outputs are strobing,
then the U4 RIOT chip is probably bad. Also note that Z15 (7432) switch enable chip
could be causing problems here too (and this also uses one gate from Z12, pins
12/13).
Strobe/Row Connector Chip In Chip Out to RIOT
S0 A1J5-2/A1J6-1 Z12 pin 2 Z12 pin 1 U4 pin 24
S1 A1J5-3/A1J6-2 Z12 pin 4 Z12 pin 3 U4 pin 23
S2 A1J5-4/A1J6-3 Z11 pin 12 Z11 pin 13 U4 pin 22
S3 A1J5-5/A1J6-4 Z11 pin 10 Z11 pin 11 U4 pin 21
S4 A1J5-6/A1J6-5 Z11 pin 6 Z11 pin 5 U4 pin 19
S5 A1J5-7/A1J6-6 Z11 pin 4 Z11 pin 3 U4 pin 18
S6 A1J6-7 Z11 pin 2 Z11 pin 1 U4 pin 17
S7 A1J5-9/A1J6-8 Z11 pin 8 Z11 pin 9 U4 pin 16
The switch matrix strobes/rows should also be tested. This is mostly chip Z11, with
two gates on Z12 also used. Check Z11's input pins 2,4,6,8,10,12 (these go directly
to the playfield switches). Then check Z11's output pins 1,3,5,9,11,13. Also Z12's
input pins 2,4 and output pins 1,3 should be checked.
In my opinion many offending CPU board issues can be attributed to a failed U4 RIOT
chip. It seems to cause more problems than it should. And often the fail is not black
and white. That is, the game will sometimes boot, but other times may not. This
situation can get worse and worse with time, until finally the game won't boot at all.
It's like the U4 RIOT internally desolves, but at a slow rate. I have seen this many
times, and it's rather odd compared to other manufacturer's games (where they
work one day, and the next day they don't, with no "sometimes it works" factor).

Unfortunately I don't have a logic probe around here but I may try and search locally to find one. That will help rule out the u4 riot chip. Unless there is another way to test it. Would the riot chip cause the z11,z12,z13,z14 chips to go bad or simply not function correctly? It seems the chips themselves are getting fried (I'm not sure which one specifically yet) because when I replaced them the game functioned "normally" for a few games. If I do get a logic probe I believe it may help me determine which chip (and even which gate on the chip?) is going bad. That may help me trace it down the line.

[ed12]

hi
the roit will cause a host of problem's
if u have a multimeter go to vdc and u can see the line's strobe and u can see the return's ie up to 5 but not nessarly 5 i find 2.5 then drop to 0 vdc
if the line's are working right u can clearly see the :strobimg-effect:
a latch high low line is not what u want on the input output side of the
interface chip's ie z11/12/13/14
as they are buffer's 1 side is high the other is low
u will want a ref.handbook and or use nte to cross them over and snag there pdf's,1 sure tell trick on the riot chip's,is the _enable line toggling..
this is a cause for concern..now if u have a batt in this unit,for testing remove 1 lead,them your machine will not keep scoring values
until u fix the matrix,and yes the slam tilt circuit is a cause for problem's
u have 1 on the door,1on the playfield,2 on the side wall of the cabinet
ed

[brad808]

So tonight I disconnected everything except the power, and display plugs. The only other thing I connected was an alligator clip so the board saw the slam switch closed. On all pins that I probed I can see voltage but not anything "moving". The voltages are simply sitting at the same value for as long as I hold the meter there. I tried with both analog meter and digital meter to see if there were problems with the digital not reading fast enough.

Are there other spots I can stick my meter to see the strobbing effect so I make sure I'm not missing it somehow? Will the other riot chips be strobbing? If all voltages remain at a constant voltage does that indicate a bad riot chip?

This is what my repair guide says

MISSING STROBES FROM THE CPU

Testing strobes from the CPU will indicate if the problems are CPU or connector related. Often the connector is usally the problem, but there are a few other checks to do.

The following chart will tell you which strobes you might be missing:

Strobe #0 at connector J5-2 and J6-1 and chip Z12-2, start at U4-24
Strobe #1 at connector J5-3 and J6-2 and chip Z12-6, start at U4-23
Strobe #2 at connector J5-4 and J6-3 and chip Z11-12, start at U4-22
Strobe #3 at connector J5-5 and J6-4 and chip Z11-10, start at U4-21
Strobe #4 at connector J5-6 and J6-5 and chip Z11- 6, start at U4-19
Strobe #5 at connector J5-7 and J6-6 and chip Z11- 4, start at U4-18
Strobe #6 at connector J6-7 and chip Z11- 2, start at U4-17
Strobe #7 at connector J5-8 and J6-8 and chip Z11- 8, start at U4-16

The strobe will be at both connectors (except Strobe 6) and will indicate if you have a connector or CPU problem. Move back to chip Z11 or 12. Then move back to U4 to the start of the matrix.

EXAMPLE: missing entire row of switch 40-44. (follow along with CPU schematic)
This indicates a missing strobe #4. Start at connector J5-6 and J6-5 (no strobe is seen), so then move on to chip Z11-6 (no storbe seen), then move on to U4-19 (strobe seen). At this point you need to make sure the strobe is making it from U4 to Z11. This strobe goes into Z11-5 (see schematic) and should be there if at U4-19. A strobe at Z11-5, but not Z11-6 would indicate a bad Z11 which would need to be replaced. No strobe at U4-19 would indicate a bad U4- RIOT (common).

A strobe found at the Z11 and Z12 as listed above, but not at J5 or J6 would probably indicate a bad connector. You are attempting to probe the connector itself or the wire in the harness, so any flawed connector pin would not get the signal from the CPU board to the connector.

It would seem that I wouldn't be missing all the strobes. Most people would have a bad pin or two from the riot chip and not the entire chip?

[ed12]

hi
 a little logic order is in need here
the riot chip's are >pia's<,they were made by both rockwell and motorola
plus intel,search the web and find what is called the i/o line's
this is were data is sent to the chip and returned from the chip
it is a 40 pin chip...1 or 3 bad line's mean's the chip is done,for the simple fact it is latching up,the olny way to tell is to remove the chip's that interface it and the diode's,leave them out,power up,if u find a high switch and or a none strobbing port,u can conculde u have a blown riot..

ed

[brad808]

OK I replaced u4 riot chip and got the game back up running again. All switches are working now   (cross fingers it doesn't crap out on me in a few more games). What a pain it was trouble shooting that thing. It seemed everytime I turned the machine on there was a different problem. Thanks for all the help.

One thing I've noticed is when I first got the machine upon boot up it would scroll "hollywood's finest" and then start showing high scores across the bottom. As of right now it comes up as just 0's but plays fine and shows credits etc fine. When I start the game it scrolls "the heat is on" as normal. Might be something simple but I'd like to sort that out as well.

Edit: Just a dip switch 

So looks like just u4 riot caused me a ton of trouble

[ed12]

hi
congrads
now enjoy the game
i once did a sc on a 80b where the switch riot was shot because some clown in toronto thought u could use :duct-tape: on the back of the board
to isolate it....

ed

[brad808]

It seems like it's going to be a really fun game but considering this is my first pinball I really have nothing to compare to I'm simply happy to be playing anything at this point. I'm not really sure what features I like/dislike in pinballs yet. I haven't even read over the game rules and scoring guide in the manual, just been staring at schematics. That being said there are a lot of cool features it has that make me believe it will be a lot of fun and hopefully lots of replay value. The fact that it's 4 player is going to be a big plus at my house and being able to steal other players captured balls to gain multiball will be fun. Hitting the captive ball is a pretty satisfying shot as well because its a fairly small target and has to be a direct shot from the flipper to get enough force to start bouncing the ball around and hitting the pop bumper inside the captive area. Reading others reviews on the machine it seems everyone enjoys the game aspect of it with it's major downside being the 80s "cheese" factor (back photo and music are unmistakably 80s  ). It seems like this game has a good feature to price ratio because once you move up a few years into the 90's almost all the machines are selling for >1000.